1. Field of the Invention
The present invention relates to a document processing apparatus for creating and editing documents.
2. Description of the Related Art
There are two systems for performing the process of calculating the position where characters should optimally be arranged on a given page, that is, for performing a composition process, using recently developed document processing apparatuses, particularly those used in the DTP field.
One system is the What You See Is What You Get (WYSIWYG) system. Widely available types of word processors correspond to this system. This is a system in which the user inputs characters of a certain size to a position corresponding to the final printing shape (layout) while the user is watching the shape on a screen. This system has the following advantages and disadvantages:
Advantages
Because the user inputs characters while watching the final screen, he is able to create any document he wishes. PA1 Excellent user interface PA1 Short documents can be easily created. PA1 It is difficult to treat bulk documents in a standardized manner. (For instance, it is difficult to write an entire chapter using a fixed character size.) PA1 A process similar to a batch process is required to create contents and indexes. PA1 It is difficult to reuse documents in other systems. PA1 A device exclusively for use with this system is required. PA1 Bulk documents can be easily treated in a standardized manner. PA1 A function for creating contents and indexes is easily adopted. PA1 The system is capable of being operated even on workstations (WS's) having standard text terminals. PA1 Because the system is of a document program type, it is difficult for laymen to operate it. PA1 The results of the process cannot be confirmed unless they are compiled and displayed. PA1 Short documents are more easily created by the WYSIWYG system than by this system.
Disadvantages
The other type of system is a batch-type system. The TEX created by Professor Knuth at Stanford University and the roff system developed by AT & T correspond to this system (refer to "Document Shaping Language" in Information Process, pages 559 to 654, by Izumi Kimura, July, 1981). FIG. 2 shows a process used in this system. A text editor 50 creates a source file 51 containing an instruction for composing a document. The source file 51 is then compiled to create an intermediate file 53 which stores the results of the composition. The results are displayed on a screen 54 or output on a printer 55.
This system has the following advantages and disadvantages:
Advantages
Disadvantages
As understood from these comparisons, the WYSIWYG and batch-type document processing systems each have advantages and disadvantages. These systems have been expanded in recent years to solve their own disadvantages. The WYSIWYG system has adopted some of the advantages of the batch-type system: for example, a batch process for contents and indexes has been added, and a style sheet has also been added to create a document in which all the pages have the same page style. On the other hand, in the batch-type system, a structured editor is used so that the user can know the type of command to be entered next time through an icon or other means, rather than the user having to directly prepare a program for documents.
Thus, recent document composing processes have become hybrids of the WYSIWYG system and the batch-type system.
In most cases, both systems create documents in monochrome, except for special cases, such as when slides or OHP's are used.
It has hitherto been difficult for the batch-type system in particular to introduce color images and graphic forms into a document in a manner independent of the type of device used.
However, because of recent development in color monitors and advanced functions of peripheral equipment, there has been a demand for a previewer which handles color documents mixed with texts, images and graphic forms, that is, which displays the results of printing and composition.
Even when color texts, images and graphic forms can be utilized by a system according to its own method, data cannot be completely exchanged with other systems.